Sealant on thermostat gasket?

[Skunksmash]

Got a couple questions about doing the thermostat gasket on 87 5.7L.

1. Do you use sealant? Like that RTV stuff. I've heard some people don't, and some people do. I just tried sealant and it leaks!

2. Does the thermostat sit on top of the gasket, or go underneath it? Strange question, but looking at it I realize that the thermostat is a lot bigger around than the hole in the gasket.

[imjeff]

No sealant. I use the good Felpro gaskets on top of the thermostat.

Jeff

[SkinnyG]

FelPro: 35562T

[hatzie]

Originally Posted by SkinnyG

FelPro: 35562T

The FelPro: 35562T raised ring gasket and some Sil-Glyde with the original water neck is one of the best things since sliced bread. Usually they're re-usable too.

Back in high school... I mounted a smallblock water neck in a 4 jaw chuck on the lathe at school and cut an o-ring groove. That worked pretty nicely to stopper up the leaks. A couple buddies did the same. I suppose I could've mounted the water neck or an intake manifold on a rotary table and cut the groove with the J-Head Bridgeport but the lathe was more accessible.

[Skunksmash]

Thanks for all the help everyone.

I did buy a felpro gasket but its not the one with the ring. Its just a plain blue one. I take it from the replies, that the waterneck leak on the 350 is a very common problem on that engine?

[Just call me Sean]

Thermostat, gasket, housing. Yes I use RTV.

[77chevyinline6]

Ive always used rtv, never game me any problems

[MountainGoat1966]

I must be old school from the prehistoric age, I smear a film of grease on the gasket.

[SkinnyG]

The FelPro gasket I posted needs nothing. It is the cat's meow, and it is re-useable! Pricey though, but I am very, very impressed with it.

[imjeff]

Originally Posted by SkinnyG

The FelPro gasket I posted needs nothing. It is the cat's meow, and it is re-useable! Pricey though, but I am very, very impressed with it.

X2! Best thing since canned Coors.

[Just call me Sean]

Technically gaskets don't need sealer, the gasket is the seal, but a little extra insurance doesn't hurt.

[bob_o]

I've always put a thin film of rtv on both sides of the gasket.

[donut]

I'll use whatever's handy. Grease, I'll use on a lot of gaskets. RTV, if the tube is a lot closer than the grease.

The key seems to be, make sure the mating surfaces are clean. Skunksmash, iirc, there is a recess on the intake manifold side where the thermostat sits, gasket over it.

[imjeff]

The gasket, housing surfac and thermostat are the same on both small and big blocks. Leaks are common due to dirty or pitted surfaces, thermostat over gasket, fancy o-ring water necks and gasket sins...crap gasket, RTV glopping, etc. A good gasket and clean surfaces are all you need.

[gmachinz]

X2 on the reusable Fel-Pro gasket! For the money and effort, I usually go with a new housing along with it.

[anubisani]

I use right stuff and gasket , but recently I had no gasket so I beaded the right stuff thick then wait for it to semi cure then place then place the cover on top

[Skunksmash]

Will any 350 waterneck work? A friend of mine bought one about a year ago and it was a cast piece of junk. When he tightened down the bolts it cracked. I'd like one that's not cast metal if possible

[imjeff]

The chrome ones are usually junk castings. There is a cast aluminum one you can get for under $10 that I've had good luck with. I usually get them from Rock Auto. I just got a couple so I can find the part number if you need it.

Jeff

[imjeff]

Just found my Rock Auto receipt from last week. It was a Four Seasons #84823 at a cost of $5.95. It has the tab for the return spring as well. Good luck!

Jeff

[Skunksmash]

Return spring? What return spring? lol

But seriously I didn't see any spring